Packing density control of carbon nanotube emitters in an anodic aluminum oxide nano-template on a Si wafer

Carbon nanotubes (CNTs) emitters in the AAO templates on a silicon wafer were fabricated. The packing density of CNTs was changed in the order of 1 × 107 − 7 × 107 tips cm− 2 depending upon the concentration of hydrogen in the reactant gas mixture. The emission current density was strongly dependent upon the packing density of the CNT emitters. Low turn-on fields of 1.6–2.1 V/μm and field enhancement factor of 1900–4970 were observed.